1. Field of the Invention
The invention relates to a rotation drive and a vibration exciter.
2. The Prior Art
In construction, vibration generators such as vibrators, shakers, or vibration bears, are used to introduce profiles into the ground, or to draw them from the ground, or also to compact ground material. The ground is excited by means of vibration, and thereby achieves a “pseudo-fluid” state. The friction between the goods to be driven in and the ground is reduced as the result of the vibration; the forward drive direction is determined by static top loads. The vibration results from the centrifugal forces of rotating imbalances that run in pairs, within the vibrator drive. Vibration generators are characterized by the effective imbalance (called “static moment” in the field of technology) and the maximal speed of rotation.
For different applications, and in order to achieve an optimal forward drive, i.e. good compaction, as a function of the goods being driven and the ground properties, it is necessary to adjust the size of the effective imbalance. German Patent Application No. DE 20 2007 006 283 U1 describes a vibration exciter in which the effective imbalance and thus the vibration can be adjusted by way of a swivel motor. In this connection, three imbalances are affixed on every imbalance shaft. The middle one of these imbalances corresponds to the sum of the two outer ones. For an adjustment, the middle imbalances are rotated relative to the other ones, step by step, by up to 180 degrees. The swivel motor, which rotates along as a shaft and stands in engagement with the other gear mechanism components by way of two gear wheels, serves to adjust the middle imbalance relative to the others. One of the gear wheels is mounted on the shaft of the swivel motor, and another is mounted on the housing.
It is a disadvantage of the previously known swivel device for adjusting the static moment that in order to supply the swivel motor with hydraulic oil, line passages are required, which are complicated to produce and are subject to wear.